Effects of charring on mass, organic carbon, and stable carbon isotope composition of wood

Influence of production variables and starting material on charcoal stable isotopic and molecular characteristics

“…Following heating over 100°C, δ 13 C values are elevated by up to 3.5‰ in bulk soil organic carbon, 2.0‰ in carbonized vegetation, 1.5‰ in plant propagules and 1.9‰ in wood (Cachier et al, 1985;Turekian et al, 1998;Werts and Jahren, 2007;Poole et al, 2002;Krull et al, 2003). In other work however, decreases of up to 1.8‰ have been observed in wood charcoal following heating up to 800°C (Jones et al, 1993, Czimczik et al, 2002Turney et al, 2006). Therefore, although available evidence suggests isotopic changes during charcoal production, both the sign and magnitude of fractionation effects is highly variable.…”

“…Therefore, changes in the proportion of different components following biomass heating could result in δ 13 C variations (e.g. Czimczik et al, 2002). Such an effect could also result in species-dependant isotopic changes, as is already observed in the rate of chemical transformations during pyrolysis (exposure to elevated temperatures in the absence of oxygen) (Labbé et al, 2006).…”

“…Characteristic changes include a reduction in intensity in the O-alkyl and di-O-alkyl regions (65-110 ppm) and an increase in aryl and O-aryl C during production of aryl and O-aryl furanlike structures (Baldock and Smernik, 2002). As temperatures increase, the chemical shift values increasingly centre at ~127ppm, typical of condensed aromatic carbon produced in both natural and laboratory-produced charcoals (Czimczik et al 2002;Simpson and Hatcher, 2004). …”

Stability and carbon isotope changes of soot and char materials during thermal oxidation: Implication for quantification and source appointment

“…Czimczik et al (2002) found that δ 13 C values of softwood and hardwood chars both became more positive during charring at 150°C, but they became more negative at higher combustion temperatures. Similar findings were reported for thermal degradation of C3 and C4 vegetation in many studies (Leavitt et al, 1982;Turekian et al, 1998;Krull et al, 2003;Das et al, 2010;Bird and Ascough, 2012).…”

Revisión de las investigaciones a nivel molecular sobre el impacto del fuego en la materia orgánica del suelo: progresos en el siglo XXI

“…Por ejemplo la respuesta de los valores de δ 13 C de la MOS afectada por el fuego está siendo objeto de debate (Saito et al, 2007;Huber et al, 2013). Algunos autores han observado un incremento relativo en los valores de δ 13 C en muestras de suelos quemados (Bowman et al, 2007;Alexis et al, 2010); sin embargo otras investigaciones muestran la falta de una tendencia clara (Czimczik et al, 2002). La Fig.…”